Issued and Outstanding Stock Options (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Long-Term Stock Incentive Plans:
Options outstanding at the beginning of year	5,618,686	6,216,805
Granted
Exercised	(20,000)	(126,394)
Forfeited	(943,975)
Expired
Options outstanding at the end of period	4,654,711	6,090,411
Options exercisable at the end of the period	4,049,149	4,325,299
Options outstanding at the beginning of year, weighted average exercise price	$ 15.74	$ 15.57
Granted
Exercised	$ 13.25	$ 14.57
Forfeited	$ 16.57
Expired
Options outstanding at the end of year, weighted average exercise price	$ 15.58	$ 15.59
Options exercisable at the end of the year, exercise price	$ 15.93	$ 16.22